Thousands of people have gathered in Bangkok to present a petition seeking a royal pardon for former Prime Minister Thaksin Shinawatra. The government has warned the crowd against violence and considers the petition illegal.

Supporters of Thaksin Shinawatra say more than four million people have signed the petition asking King Bhumipol Adulyadej to pardon the former prime minister.

The petition is to be presented to the Royal Palace Monday, after a rally of thousands of Mr. Thaksin's supporters, known as red shirts.

Last year, he was convicted of abuse of power and sentenced to two years in jail, but he fled the country. The charge stemmed from a land deal involving his former wife.

The government of Prime Minister Abhisit Vejjajiva dismisses the petition as a political move, and says it will not succeed because Mr. Thaksin needs to serve time in jail to meet the legal requirements for a pardon.

At a recent rally supporting the petition, Kokaew Pikulthong said many of his fellow red shirts think Mr. Thaksin did not receive a fair trial.

"In my point of view, I think the people show this because the people [think] Mr. Thaksin received injustice [from the] system," he said. "Another thing is some people feel troubled because of unskilled government that Mr. Abhisit cannot show successful policy to do anything to improve their life."

In April red shirt supporters forced the government to abandon an international meeting after they broke into a hotel where the conference was taking place. Then the government had to employ emergency powers to end street demonstrations in Bangkok.

The government has warned Mr. Thaksin's supporters against violence at Monday's rally. There is concern that backers of a politician allied with the government could clash with the red shirts.

Thailand's political landscape is deeply divided. Mr. Thaksin maintains strong support among farmers and urban poor. But many in the middle class accused him of abusing his power and of being corrupt. He was ousted from power in a military coup in September 2006.

On the other hand, many Thais consider Mr. Abhisit's government to be ineffectual. There is some pressure on him to call elections later this year or early next.